Hitherto, there are used electronic equipments, e.g., image pick-up apparatuses such as video camera and/or digital still camera, mobile telephone, and/or personal computer, etc. using, as power supply, battery pack where a secondary battery such as lithium ion battery, NiCd battery or nickel-hydrogen battery, etc. is included.
In the battery pack used in electronic equipments of this kind, there are included therewithin, e.g., a microcomputer for performing residual quantity calculation of the battery, and/or communication to and from the electronic equipment using such battery pack as a power supply, peripheral circuits of the microcomputer, and a circuit for detecting the state of battery cell, which is necessary for performing residual quantity calculation of battery, etc. As a battery pack of this kind, there is a battery pack described in the Japanese Patent Application Laid Open No. 1997-297166 publication.
Moreover, portable or mobile information processing apparatuses such as PDA (Personal Digital Assistant), etc. have network connecting function, whereby there is performed user authentication processing to confirm that concerned user is authorized user in order to comply with electronic settlement using such network connecting function with enhancement of processing ability. For example, there is performed, e.g., a method of performing communication of information relating to authentication between charging unit and control means within the mobile information processing apparatus to protect personal information and secret information, which are stored within the mobile information processing apparatus, on the basis of result of the authentication confirmation. As an equipment having a function of this kind, there is an equipment described in the Japanese Patent Application Laid Open No. 2004-310387 publication.